<script setup>
import { ref, watch } from 'vue';
import { useMouseInElement } from '@vueuse/core';

//props适配图片列表
defineProps({
    imageList: {
        type :Array,
        default: () => []
    }
})

//1.小图切换大图
const activeIndex =ref(0)

const enterhandler =(i)=>{
    activeIndex.value =i
}

//2.获取鼠标相对位置
const target =ref(null)
const { elementX , elementY , isOutside } =useMouseInElement(target)

//3.控制滑块跟随鼠标移动（监听elementX , elementY的变化 重新设置left/top）
const left =ref(0)
const top =ref(0)
const positionX =ref(0)
const positionY =ref(0)

watch([elementX , elementY] ,() => {
    //有效范围内控制滑块距离
    //横向
    if(isOutside.value) return

    if(elementX.value >100 && elementX.value<300 ){
        left.value =elementX.value - 100
    }
    //纵向
    if(elementY.value >100 && elementY.value<300 ){
        top.value =elementY.value - 100
    }

    //处理边界
    if(elementX.value >300 ){ left == 200}
    if(elementX.value <100 ){ left == 0}

    if(elementY.value >300 ){ top == 200}
    if(elementX.value <100 ){ top == 0}

    //控制大图显示
    positionX.value = -left.value * 2
    positionY.value = -top.value * 2
})


</script>


<template>
  <div class="goods-image">
    <!-- 左侧大图-->
    <div class="middle" ref="target">
      <img :src="imageList[activeIndex]" alt="" />
      <!-- 蒙层小滑块 -->
      <div class="layer" v-show="!isOutside" :style="{ left: `${left}px`, top: `${top}px` }"></div>
    </div>
    <!-- 小图列表 -->
    <ul class="small">
      <li v-for="(img, i) in imageList" :key="i" @mouseenter="enterhandler(i)" :class="{active : i === activeIndex}">
        <img :src="img" alt="" />
      </li>
    </ul>
    <!-- 放大镜大图 -->
    <div class="large" :style="[
      {
        backgroundImage: `url(${imageList[activeIndex]})`,
        backgroundPositionX: `${positionX}px`,
        backgroundPositionY: `${positionY}px`,
      },
    ]" v-show="!isOutside" ></div>
  </div>
</template>

<style scoped lang="scss">
.goods-image {
  width: 480px;
  height: 400px;
  position: relative;
  display: flex;

  .middle {
    width: 400px;
    height: 400px;
    background: #f5f5f5;
  }

  .large {
    position: absolute;
    top: 0;
    left: 412px;
    width: 400px;
    height: 400px;
    z-index: 500;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    background-repeat: no-repeat;
    // 背景图:盒子的大小 = 2:1  将来控制背景图的移动来实现放大的效果查看 background-position
    background-size: 800px 800px;
    background-color: #f8f8f8;
  }

  .layer {
    width: 200px;
    height: 200px;
    background: rgba(0, 0, 0, 0.2);
    // 绝对定位 然后跟随咱们鼠标控制left和top属性就可以让滑块移动起来
    left: 0;
    top: 0;
    position: absolute;
  }

  .small {
    width: 80px;

    li {
      width: 68px;
      height: 68px;
      margin-left: 12px;
      margin-bottom: 15px;
      cursor: pointer;

      &:hover,
      &.active {
        border: 2px solid $xtxColor;
      }
    }
  }
}
</style>